Electrical connection between movable parts



Nov. 18, 1969 J. HUS 3,479,444

ELECTRICAL CONNECTION BETWEEN MOVABLE PARTS Filed July 27, 1967 INVENTOR. Joizmmes Has United States Patent 3,479,444 ELECTRICAL CONNECKIOD; BETWEEN MOVABLE P RT Johannes Hus, Trumbull, Conn., assiguor to Burndy Corporation, a corporation of New York Filed July 27, 1967, Ser. No. 656,571 Int. Cl. H02g 15/08 U.S. Cl. 174-86 1 Claim ABSTRACT OF THE DISCLOSURE An electrical connector in the form of a helical strip adapted to be coupled at its opposite ends to the substantially aligned, axially spaced apart end portions of two electrical conductors. The helical strip being formed in one embodiment, from a laminated cylindrical body having a helical slot cut intermediate the ends thereof.

These requirements include particularly high current car-- rying characteristics; ability to permit relatively large deflections and to prevent high deflection forces; and optimum suppression of corona discharge effects.

The prior connectors which meet these requirements, individual elements which are mechanically connected together, so as to permit relative motion therebetween. The use of movable mechanical couplings tends to increase the cost of these connectors by requiring additional production and assembly processes, in addition to presenting significant weight and size problems.

Accordingly, it is an object of the present invention to provide an electrical connector which is of simple and inexpensive construction, which is light in weight, and which is particularly suited to establishing movable mechanical and electrical connections between bus-bar conductors.

A further object is to provide such a connector which is of particularly compact construction and may be fabricated as a unitary structure.

These and other objects, features, and advantages of this invention will be made more apparent by reference to the following specification, taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a side elevation view of one form of electrical connector constructed in accordance with this invention;

FIGURE 2 is a transverse section view taken along line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary side View, partially in section, of another form of connector constructed in accordance with this invention;

FIGURE 4 is a fragmentary side elevation view of still another form of connector constructed in accordance with this invention;

FIGURE 5 is a transverse section view, illustrating how a modified form of the connector of FIGURE 4 would appear along section line 55;

FIGURE 6 is a sectional view similar to FIGURE 5 showing another modified means for coupling the connector of FIGURE 4 to a bus bar conductor;

FIGURE 7 is a fragmentary side view of another form of connector constructed in accordance with this invention.

Referring now more particularly to the drawings, the

3,479,444 Patented Nov. 18, 1969 main body 10 of the connector, which may be formed A of any suitable conventional conductive material, is seen to include a pair of helical strip members 12, 14, preferably of rectangular cross section and secured such as by Welding, to two terminal rings or collars 16, 18. The collars in turn are secured, such as by welding to the axial- 1y aligned bus bars 20, 22 which are to 'be electrically and mechanically joined together. It will be appreciated that the connector body 10 may be formed of a single helical strip; however, the use of two or more helical strips permits the use of narrow spacing between adjacent turns, with resultant reduction in undesirable corona effects. The number of turns for the strips will depend upon the bus bar size, Weight, etc. The terminal rings or collars 16, 18 which are preferably of the same material as helical strips 12, 14 should have a slip fit on the bus bars and may have a smaller inside diameter than the helical strip members.

FIGURE 3 represents an embodiment similar to FIG- URE 1 in which helical strips 24, 26 shoWn secured at one end to collar 28 are formed of a plurality of laminated strips 30 of conductive material instead of the solid construction of FIGURE 1. Comparison test of the solid construction and the laminated construction have shown that the laminated construction is highly advantageous from the standpoint of reduced size and weight of the connector for given current carrying and deflection characteristics.

The advantage of laminated construction may be seen in the following example. The design requirements for a typical application might bef An aluminum expansion connector for a 6 inch IPS aluminum 'bus conductor, able to carry 4200 amperes, able to take up plus and minus 3 inches of bus expansion at a force less than lbs. For such an application, a non-laminated strip would be 8 inches wide and 0.7 inch thick. The strip would be 2692 inches long and weigh 4521 lbs.

However, if the thickness is divided into, for example, 8 laminated, in accordance with this invention, each 0.090 inch thick, the length of the connector will drop to 62 inches and its weight to 88 lbs.

And further, if the thickness is divided into 24 laminates, each 0.030 inch thick, the required length of the connector will be merely 21 inches and its weight only 15 lbs.

There is shown in FIGURE 4 a simplified modification of the helical connectors of FIGURES l and 3. In this embodiment, helical strips 32, 34, which may be of single piece or laminated construction, are directly affixed to the bus bars by suitable means such as brazing, Welding or adhesive. This modification eliminates the use of the collars utilized in the embodiments of FIGURES 1 and 3.

In addition to the above means for securing the free ends of the helical strips 32, 34, it is possible to use a bolt 36 and an internally threaded seat 38 with enlarged head 40 for securing the helical strip members to the busbars. This embodiment is particularly useful when only a single helical strip member 42 is used such as shown in FIGURE 6. In this embodiment, the threaded seat 38 is placed in a suitable opening 44 in each bus bar to receive the bolt 36 which passes though suitable openings 46, 48 in the helical strip member 42 and the bus bar respectively. The bolt 36 is preferably seated within an enlarged opening 50 in helical strip member 42 to eliminate any projecting surfaces to reduce possible corona effects. The use of threaded seat 38 with smooth enlarged head 40 rather than a conventional nut also serves to reduce possible corona effects.

There is shown in FIGURE 7 another embodiment of the invention in which a connector 52 includes a tubular body member 54 which may be of single piece or laminated construction having a continuous helical slit 56 formed therein. Although only one helical slit is shown, additional slits may be used depending on design, application, and corona requirements. The helical slit 56 terminates short of the ends of the tubular body member 54 forming an integral ring or collar 58 which are secured to the bus bars by the use of bolts 60 or by other suitable means such as brazing or welding. It will be appreciated, that if bolts 60 are used, integral ring or collar 58 should have a tight interference fit on the bus bars to assure a good electrical connection.

V I claim:

1. An electrical and mechanical connection providing a continuous electrical path between two relatively movable parts, comprising:

a first substantially tubular electrical conductor, having an end portion; a second substantially tubular electrical conductor, having an end portion spaced from said end portion of said first substantially tubular electrical conductor along a substantially common central axis;

An electrically conductive connection member formed of a plurality of flexible laminar layers secured at References Cited UNITED STATES PATENTS 2,306,527 12/ 1942 Daniels.

2,927,953 3/1960 Staller l74-l2 XR 3,355,542 11/1967 Finn 17479 FOREIGN PATENTS 1,034,634 6/1966 Great Britain.

20 DARRELL L. CLAY, Primary Examiner US. Cl. X.R. 

